diff --git a/src/tc_scf/rh_tcscf_diis.irp.f b/src/tc_scf/rh_tcscf_diis.irp.f
index 5901911c..61355498 100644
--- a/src/tc_scf/rh_tcscf_diis.irp.f
+++ b/src/tc_scf/rh_tcscf_diis.irp.f
@@ -1,5 +1,10 @@
 ! ---
 
+! TODO
+! level shift of SCF is well adapted
+! for 0.5 x F
+! 
+
 subroutine rh_tcscf_diis()
 
   implicit none